1、 Definition of Explosion proof and Anti corrosion Low Voltage Electrical Appliances

Explosion proof and anti-corrosion low-voltage electrical appliances refer to electrical appliances used in indoor and outdoor explosive hazardous areas with explosive gas mixtures and corrosive media.

2、 Explosion proof and anti-corrosion low-voltage electrical appliances are divided into the following five types according to their protection types:

(1) Indoor explosion-proof and moderately corrosion-resistant type

(2) Indoor explosion-proof and corrosion-resistant type

(3) Outdoor explosion-proof and light corrosion resistant type

(4) Outdoor explosion-proof and moderately corrosion-resistant type

(5) Outdoor explosion-proof and corrosion-resistant type

3、 Technical requirements for explosion-proof and anti-corrosion low-voltage electrical appliances

(1) Normal operation must meet the climatic and biological conditions listed in Table 1, as well as the environmental conditions for chemical and mechanical active substances listed in Table 2.

(2) Has anti-corrosion properties

a. The insulation resistance value between the shell and conductive parts of the electrical appliance, as well as between conductive parts that are insulated from each other, shall not be less than 2M Ω

b. The dielectric performance of electrical appliances should comply with the relevant provisions of GB/T 14048.1-1993

c. The action and operational performance of electrical appliances should be flexible and reliable, in accordance with the provisions of product standards,

d. Conductive components, magnetic components, metal structural components, and fasteners inside the casing must not exhibit obvious corrosion, such as copper green, rust, etc. (excluding the pole surface of the iron core)

e. The paint layer on the surface of the shell should not be loose or visibly wrinkled, and bubbles with a diameter greater than 1mm should not be commonly present. The maximum diameter of individual large bubble pairs should not exceed 10mm on castings and 5mm on steel plate components. There should be no bottom metal corrosion (except for welding seams, casting surface particles, sharp corners, and mechanical damage)

f. The plastic shell and the plastic parts on the shell must not bubble, deform, or crack

g. Rubber parts shall not be corroded, layered, brittle, deformed or sticky, and the hardness change value of sealing rings and gaskets shall not exceed 20% before the test.

h. The nameplate shall not corrode, curl up or fall off, and the handwriting on the nameplate shall be kept clear

i. The explosion-proof surface of explosion-proof electrical appliances must not corrode

j. The conductive parts and fasteners inside the junction box must not have obvious corrosion points.

(3) Has explosion-proof performance

After corrosion testing, the explosion-proof performance of electrical appliances must comply with the relevant requirements of GB3836

(4) Shell protection performance

The protective performance of the casing of electrical appliances should not be lower than the provisions of IP54

(5) Fasteners on the casing

All steel fasteners (bolts, screws, washers, etc.) on the casing of electrical appliances should be galvanized or passivated on their surfaces, or other anti-corrosion treatments should be applied. For strongly corrosive electrical appliances, after assembly, any exposed fasteners on the casing should be sealed with nitrile or chloroprene rubber sealant.

(6) Grounding bolt

The grounding bolts of electrical appliances should be made of stainless metal materials or undergo reliable anti-corrosion treatment

(7) Painting on the surface of the casing

The paint on the surface of the electrical casing should comply with the requirements of JB 2420. The outer surface of outdoor explosion-proof and anti-corrosion low-voltage electrical appliances should be coated with light colored paint (gray, silver gray, light gray, and white).

(8) Anti corrosion treatment of explosion-proof surface

The explosion-proof surface of metal materials in explosion-proof electrical appliances should be treated with anti-corrosion treatment, allowing the application of rust proof grease that can prevent corrosion and maintain explosion-proof performance.

(9) Temperature rise of outdoor explosion-proof and anti-corrosion low-voltage electrical appliances

When designing outdoor explosion-proof and anti-corrosion low-voltage electrical appliances, the impact of sunlight exposure on temperature rise should be considered. The temperature rise design can be carried out according to the maximum ambient temperature of 40 ° C, but a certain margin must be left to offset the impact of sunlight exposure. The values of temperature rise margin are shown in Table 3.

(10) Low temperature performance of outdoor explosion-proof and anti-corrosion low-voltage electrical appliances

When the operating temperature of outdoor explosion-proof and anti-corrosion low-voltage electrical appliances is below -20 ° C, the impact of low temperature environment on electrical performance should be considered. Outdoor explosion-proof and anti-corrosion low-voltage electrical appliances should be designed with shell materials, electrical components, connecting wires, structural components, oil, etc. that have good low-temperature resistance to ensure reliable electrical performance and explosion-proof safety performance under low temperature conditions.

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